Quantum Sensors | JSQ-421/422-SS Series - Digital Outputs
Measure photosynthetically active radiation.
Spectral Response
The original Apogee quantum sensor works well for broadband radiation
sources (sun, and high pressure sodium, metal halide, cool white fluorescentlamps).

Accurate, Stable Measurements
Calibration in controlled laboratory conditions is traceable to an NIST lamp.
Quantum sensors are cosine-corrected, with directional errors less than ± 5 %at a solar zenith angle of 75°. Long-term non-stability determined frommultiple replicate quantum sensors in accelerated aging tests and field
conditions is less than 2 % per year.

Rugged, Self-cleaning Housing
Patented domed shaped sensor head (diffuser and body) facilitate runoff
of dew and rain to keep the sensor clean and minimize errors caused by
dust blocking the reduced path. Sensors are housed in a rugged anodized
aluminum body and electronics are fully potted.

Output Options

Digital output options include SDI-12 and ModBus communication
protocol. Sensor is also available in multiple analog output options,attached to a hand-held meter with digital readout, and as a ‘digital’smart sensor that uses USB communication and custom software tointerface directly to a computer.

Mounting
The AM-110 mounting bracket facilitates mounting the AL-100 leveling plate
to a mast or pipe. The bubble-level in the plate makes leveling simple andaccurate.

Typical Applications
PPFD measurement over plant canopies in outdoor environments,greenhouses, and growth chambers, and reflected or under-canopy(transmitted) PPFD measurements in the same environments. Quantumsensors are also used to measure PPFD in aquatic environments, including salt
water aquariums where corals are grown.

Cosine Response

Calibration Traceability
Mean cosine response of twenty-three JSQ original
quantum sensors (error bars represent two
standard deviations above and below mean).
Cosine response measurements were made by directside-by-side comparison to the mean of four reference
thermopile pyranometers, with solar zenith angledependent factors applied to convert total shortwave
radiation to PPFD. Blue points represent the AM
response and red points represent the PM response.

Apogee Instruments JSQ series quantum sensors are calibrated through side-by-side comparison to the mean of four model JSQ-110 or JSQ-120
transfer standard quantum sensors under high output T5 cool whit fluorescent lamps. The transfer standard quantum sensors are calibrated throughside-by-side comparison to the mean of at least three LI-COR model LI-190R reference quantum sensors under high output T5 cool white fluorescentlamps. The reference quantum sensors are recalibrated on a biannual schedule with a LI-COR model 1800-02 and quartz halogen lamp are traceable
to the National Institute of Standards and Technology (NIST).

Dimensions

11.0 mm

44.0 mm

Spectral Response#10-32 UNF
Tapped Hole

Mean spectral response of six JSQ original quantum
sensors (error bars represent two standard
deviations above and below mean) compared
to PPFD weighting function. Spectral response
measurements were made at 10 nm increments acrossa wavelength of 300 to 800 nm in a monochromatorwith an attached electric light source. Measured
spectral data from each quantum sensor werenormalized by the measured spectral response of themonochromator/electric light combination, which
was measured with a spectroradiometer

23.5 mm
8.5 mm

JSQ-421-SS
Input Voltage Requirement
Current Drain
Calibration Uncertainty
Measurement Repeatability

Temperature Response
Mean temperature response of eight JSQ original
quantum sensors (errors bars represent two
standard deviations above and below mean).
Temperature response measurements were madeat 10 C intervals across a temperature range ofapproximately -10 to 40 C in a temperature controlledchamber under a fixed, broad spectrum, electric lamp.
At each temperature set point, a spectroradiometer
was used to measure light intensity from the lampand all quantum sensors were compared to thespectroradiometer. The spectroradiometer wasmounted external to the temperature control
chamber and remained at room temperature during
the experiment.

JSQ-422-SS
4.5 to 24 V DC

0.6 mA (quiescent), 1.3 mA (active)

12.6 mA (quiescent), 13.5 mA (active)±5%
Less than 0.5 %Long-term Drift

Less than 2 % per year

Non-linearity

Less than 1 % (up to 4000 µmol m-2 s-1)

Response Time

0.6 s, time for detector signal to reach 95 % following a step change; fastest
data transmission rate for SDI-12 circuitry is 1 s

320 msField of View

180°

Spectral Range

410 to 655 nm (wavelengths where response is greater than 50% of maximum)

Spectral Selectivity
Directional (Cosine) Response

Less than 10 % from 469 to 653 nm± 5 % at 75° zenith angle

Temperature Response

0.06 ± 0.06 % per C

Operating Environment-40 to 70 C; 0 to 100 % relative humidity; can be submerged in water up to depths of 30 m

Dimensions

44.0 mm height, 23.5 mm diameter

Mass117 g (with 5 m of lead wire)Cable

5 m of shielded, twisted-pair wire; additional cable available in multiples of 5 m; santoprene rubber jacket (high water
resistance, high UV stability, flexibility in cold conditions); pigtail lead wires

Warranty

4 years against defects in materials and workmanship